Surgical Infection Flashcards
What is an SSI?
A surgical site infection. It is one that develops at the operative site within 30 days of surgery or up to a year after surgery if implants are placed.
What are the signs of an SSI?
- Pain/ tenderness
- Localised swelling/ heat/ redness
- Discharge/ drainage from incision
- Systemic signs e.g pyrexia
- Wound dehiscence (breakdown)
- Abscess
What are the possible consequences of an SSI?
- Welfare problems
- Wound breakdown
- Prolonged recovery
- Delayed healing
- Systemic illness e.g. septicaemia
- Costs of prolonged treatment/ hospitalisation
What does the bacterial burden have to exceed in a wounds to develop an infection?
More than 10^6 bacteria per gram of tissue
What are the 3 sources of bacteria for a wound?
1) Exogenous
2) Endogenous
3) Nosocomial (infection picked up in hospital)
What is a HAI?
Hospital acquired infection or nosocomial
- infection acquired in hospital by a patient admitted for a different reason other than the infection.
What are the different stages for classification of surgical wounds contamination?
1) clean
2) clean-contaminated
3) contaminated
4) dirty
Describe a clean wound scenario
- Elective, non traumatic procedure done with no break in aseptic technique.
- No acute inflammation
- No entry to respiratory tract, GI or urinary tracts
- No requirement for perioperative or postoperative antibiotics
- UNLESS it lasted more than 90 minutes, orthapaedic implants were use or there was significant tissue trauma
- Skin contaminant bacteria often Staphylococcus spp.
Describe a clean- contaminated surgery scenario
- Minor break in aseptic technique
- Entry into respiratory tract, GI or urinary tracts without significant contamination
- Antibiotics administered, often a perioperative single dose IV
Describe a contaminated surgery scenario
- Traumatic wound more than 4 hours old
- Break in aseptic technqiue
- Spillage from viscus (GIT, pyometra, UG tract)
- Antibiotics needed, both peri and postoperatively
- Broad spec possibly including anaerobes
Describe a dirty (infected) surgery scenario
- Traumatic wound more than 4 hours old with devitalised tissue or foreign material
- Perforated viscus
- Bacterial infection, abscess, pus
- Antibiotics needed, therapeutic course not prophylactic
Describe the patient factors that influence the likelihood
- General health e.g. hypothyroidism?
- Hypoalbuminaemia
- Functional state of host defences (age, BCS, malnutrition, systemic disease,drug therapy e.g. corticosteroids)
List some surgical problems that can increase the chances of an SSI developing?
- Orthopeadic vs soft tissue surgeries have different risk levels
- Aseptic technique
- Duration of surgery
- Foreign material e.g. sutures/ implants
Why are sutures a site of infection?
- Foreign material= body reacts to it (inflammatory response)
- When implanted the sutures are rapidly coated with tissue protein which created sites for bacterial colonisation
- This colonisation can lead to biofilm formation
- Biofilm increases the difficulty of treating an infection
What is a biofilm?
A structured community of bacterial cells enclosed in a self produced polymeric matrix and adherent to an inert or living surface
-Once developed the biofilm let bacteria in to make it more resistant to antibiotics
